1. Field of the Invention
This invention relates to optical axis adjustable binoculars, and more specifically, to binoculars capable of adjusting the displacement of an optical axis caused between a pair of right and left optical systems.
2. Related Background Art
In general, there are conventionally employed arrangements for adjusting an optical axis by moving the position of a prism as a mechanism for adjusting the displacement of an optical axis caused between a pair of right and left optical systems in binoculars. For example, in binoculars employing Porro prisms, there is practically used an arrangement for adjusting the displacement of an optical axis caused between a pair of optical systems disposed on the right and the left side by sliding the prism in its long bide direction.
Further, in binoculars employing roof prisms, there is practically used an arrangement for adjusting the displacement of an optical axis caused between a pair of optical systems disposed on the right and the left side by moving the two prisms as a unit.
However, according to the conventional optical axis adjusting mechanisms in the binoculars as described above, a lot of manpower is required in manufacture because fine positional adjustment is necessary. Further, since there is also a problem that a skilled technology is necessary for jobs for adjustment, it is difficult to effectively adjust an optical axis.